Since the 2010s, plastic dishes, usually disposable, are also common.
Petri dishes are often covered with a shallow transparent lid, resembling a slighly wider version of the dish itself. The lids of glass dishes are usually loose-fitting. Plastic dishes may have close-fitting covers that retard drying of the contents. Alternatively, some glass or plastic versions may have small holes around the rim, or ribs on the underside of the cover, to allow for ventilation of the air space over the culture and avoid water condensation that may be a problem that needs some attention.
Some Petri dishes, especially plastic ones, usually feature rings and/or slots on their lids and bases so that they are less prone to sliding off one another when stacked.
Small Petri dishes may have a protruding base that can be secured on a microscope stage for direct examination 
Petri dishes may have grids printed on the bottom to help in measuring the density of cultures.
A multiwell plate is a single transparent container with an array of flat-bottomed cavities, each being essentially a small Petri dish. It makes it possible to inoculate and grow dozens or hundreds of independent cultures of dozens of samples at the same time. Besides being much cheaper and convenient than separate dishes, the multiwell plate is also more amenable to automated handling and inspection.
The dishes are then left undisturbed for hours or days while the organism grows, possibly in an incubator. They are usually covered, or placed upside-down, to lessen the risk of contamination from airborne spores.
Virus or phage cultures require that a population of bacteria be grown in the dish first, which then becomes the culture medium for the viral inoculum.
While Petri dishes are widespread in microbiological research, smaller dishes tend to be used for large-scale studies in which growing cells in Petri dishes can be relatively expensive and labor-intensive.
Contamination detection and mapping
Petri dishes can be used to visualize the location of contamination on surfaces, such as kitchen counters and utensils, clothing, food preparation equipment, or animal and human skin.
For this application, the Petri dishes may be filled so that the culture medium protrudes slightly above the edges of the dish to make it easier to take samples on hard objects. Shallow Petri dishes prepared in this way are called Replicate Organism Detection And Counting (RODAC) plates and are available commercially.
Petri dishes also make convenient temporary storage for samples, especially liquid, granular, or powdered ones, and small objects such as insects or seeds. Their transparency and flat profile allows the contents to be inspected with the naked eye, magnifying glass, or low-power microscope without removing the lid.
In popular culture
The Petri dish is one of a small number of laboratory equipment items whose name entered popular culture. It is often used metaphorically, e. g. for a contained community that is being studied as if they were microorganisms in a biology experiment, or an environment where original ideas and enterprises may flourish.
^ abGary Singer (2018): "Sonder, in the City". Quote: As a native New Yorker, I tend to think of this city as a giant petri dish, in which some of the greatest breakthroughs, inventions, and audacious ideas have been nurtured to fruition. In Angela Dews (ed.) Still, in the City: Creating Peace of Mind in the Midst of Urban Chaos, p. 40. ISBN978-1510732346
^ abIsabel Slone (2018): "What Does the Mall Goth Nostalgia Trend Really Mean?". Quote: "mall goth" was a style of dress that combined the hallmarks of punk, goth and metal subcultures and thrived like bacteria in the petri dish of the early 2000s. Online article in the Fashion Magazine website, May 22, 2018. Accessed on 2019-10-25.
^Lemmen, Sebastian W.; Häfner, Helga; Zolldann, Dirk; Amedick, Günter; Lutticken, Rüdolf (2001). "Comparison of two sampling methods for the detection of Gram-positive and Gram-negative bacteria in the environment: Moistened swabs versus Rodac plates". International Journal of Hygiene and Environmental Health. 203 (3): 245-48. doi:10.1078/S1438-4639(04)70035-8. PMID11279821.
^Sonja Bäumel (2009): "Oversized petri dish". Culture of microroganisms from the artist's skin pressed onto a body-size culture plate, photographed over the span of 44 days. Part of her (In)visible membrane project. Wageningen, Germany. Accessed on 2019-10-25.
^Scott Sutton (2007): "Microbial Surface Monitoring", p. 78. Chapter 5 of Anne Marie Dixon (ed.), Environmental Monitoring for Cleanrooms and Controlled Environments. ISBN978-1420014853
^Géraldine Daneau, Elie Nduwamahoro, Kristina Fissette, Patrick Rüdelsheim, Dick van Soolingen, Bouke C. de Jong, Leen Rigouts (2016): "Use of RODAC plates to measure containment of Mycobacterium tuberculosis in a Class IIB biosafety cabinet during routine operations." International Journal of Mycobacteriology, volume 5, issue 2, pp. 148-54. doi:10.1016/j.ijmyco.2016.01.003